20 wk old retains wind - shall I change formula?

[Hillbilly]

DS has 2 formula feeds a day and I use Aptamil. When I try to settle him for his naps, which is usually an hour or so after a feed, he often has trapped wind which takes ages to bring up. He also wakes up in the night screaming with wind.

Should I consider changing formula to Cow and Gate Comfort or something else?

I forgot to add - he has only been having ff for a week so could it be that his system is just not used to it yet?